Robots are useful in a variety of civilian, military, and law enforcement applications. For instance, some robots may inspect or search buildings with structural damage caused by earthquakes, floods, or hurricanes, or inspect buildings or outdoor sites contaminated with radiation, biological agents such as viruses or bacteria, or chemical spills. Some robots carry appropriate sensor systems for its inspection or search tasks. Robots designed for military applications may perform operations that are deemed too dangerous for soldiers. For instance, the robot can be used to leverage the effectiveness of a human “pointman.” Law enforcement applications include reconnaissance, surveillance, bomb disposal and security patrols.
Small, man-portable robots are useful for many applications. Often, robots need to climb stairs or other obstacles. Generally, a small robot must span at least three stair corners to climb stairs effectively, and must maintain its center of gravity in a central disposition to keep from sliding down the stairs (center of gravity toward lower stair) or from flattening out on a stair (center of gravity toward the upper stair.)
When the size or length of a robot reaches a certain small size relative to the obstacle or stair it must climb, the robot's center of gravity usually has a deleterious effect on climbing ability. What is needed, therefore, is a robot design that can climb obstacles that are large relative to the size of the robot.